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drm/amdgpu: remove ctx->lock

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KMD reports a warning on holding a lock from drm_syncobj_find_fence,
when running amdgpu_test case “syncobj timeline test”.

ctx->lock was designed to prevent concurrent "amdgpu_ctx_wait_prev_fence"
calls and avoid dead reservation lock from GPU reset. since no reservation
lock is held in latest GPU reset any more, ctx->lock can be simply removed
and concurrent "amdgpu_ctx_wait_prev_fence" call also can be prevented by
PD root bo reservation lock.

call stacks:
=================
//hold lock
amdgpu_cs_ioctl->amdgpu_cs_parser_init->mutex_lock(&parser->ctx->lock);
…
//report warning
amdgpu_cs_dependencies->amdgpu_cs_process_syncobj_timeline_in_dep \
->amdgpu_syncobj_lookup_and_add_to_sync -> drm_syncobj_find_fence \
-> lockdep_assert_none_held_once
…
amdgpu_cs_ioctl->amdgpu_cs_parser_fini->mutex_unlock(&parser->ctx->lock);

Signed-off-by: Ken Xue <Ken.Xue@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Ken Xue 2022-02-11 16:18:46 -05:00 committed by Alex Deucher
parent 8bbd4d83a6
commit 461fa7b0ac
3 changed files with 11 additions and 8 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

16
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
View file

@ -127,8 +127,6 @@ static int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, union drm_amdgpu_cs
goto free_chunk;
}
mutex_lock(&p->ctx->lock);
/* skip guilty context job */
if (atomic_read(&p->ctx->guilty) == 1) {
ret = -ECANCELED;
@ -585,6 +583,16 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
}
}
/* Move fence waiting after getting reservation lock of
* PD root. Then there is no need on a ctx mutex lock.
*/
r = amdgpu_ctx_wait_prev_fence(p->ctx, p->entity);
if (unlikely(r != 0)) {
if (r != -ERESTARTSYS)
DRM_ERROR("amdgpu_ctx_wait_prev_fence failed.\n");
goto error_validate;
}
amdgpu_cs_get_threshold_for_moves(p->adev, &p->bytes_moved_threshold,
&p->bytes_moved_vis_threshold);
p->bytes_moved = 0;
@ -700,7 +708,6 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error,
dma_fence_put(parser->fence);
if (parser->ctx) {
mutex_unlock(&parser->ctx->lock);
amdgpu_ctx_put(parser->ctx);
}
if (parser->bo_list)
@ -944,7 +951,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev,
if (parser->job->uf_addr && ring->funcs->no_user_fence)
return -EINVAL;
return amdgpu_ctx_wait_prev_fence(parser->ctx, parser->entity);
return 0;
}
static int amdgpu_cs_process_fence_dep(struct amdgpu_cs_parser *p,
@ -1363,7 +1370,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
goto out;
r = amdgpu_cs_submit(&parser, cs);
out:
amdgpu_cs_parser_fini(&parser, r, reserved_buffers);

2
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
View file

@ -230,7 +230,6 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev,
kref_init(&ctx->refcount);
spin_lock_init(&ctx->ring_lock);
mutex_init(&ctx->lock);
ctx->reset_counter = atomic_read(&adev->gpu_reset_counter);
ctx->reset_counter_query = ctx->reset_counter;
@ -352,7 +351,6 @@ static void amdgpu_ctx_fini(struct kref *ref)
}
}
amdgpu_ctx_set_stable_pstate(ctx, AMDGPU_CTX_STABLE_PSTATE_NONE);
mutex_destroy(&ctx->lock);
kfree(ctx);
}

1
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
View file

@ -49,7 +49,6 @@ struct amdgpu_ctx {
bool preamble_presented;
int32_t init_priority;
int32_t override_priority;
struct mutex lock;
atomic_t guilty;
unsigned long ras_counter_ce;
unsigned long ras_counter_ue;